Soon after the Love Canal situation first came to public health attention, the NYSDH began an analysis of cancer incidence patterns in the Canal area using data from the long-established statewide New York Cancer Registry (Janerich, et al, 1981), comparing observed numbers of cases in the Canal area with expected numbers based on incidence rates elsewhere in New York state as a whole. The census tract in which the Love Canal is located was used to define the Love Canal population (total 1970 population: 4897). Table A and B summarize the findings of this study.
| TABLE A: Incidence of Selected Cancers in Residents of the Love Canal Census Tract by Time Period, 1955-1977 | |||||||
| Male Number of Cases |
Female Number of Cases |
||||||
| Time Period | Type of Cancer | Obs | Exp. | SIR* | Obs | Exp. | SIR |
| 1955-65 | Liver Lymphoma Leukemia |
0 3 2 |
0.4 2.5 213 |
0.0 1.2 0.9 |
2 2 3 |
0.3 1.8 1.7 |
6.7 1.1 1.8 |
| TABLE B: Incidence of Selected Cancers in Residents of the Love Canal Census Tract, by Cancer Site, 1966-1977 | ||||||
| Male Number of Cases |
Female Number of Cases |
|||||
| Cancer Site | Obs. | Exp. | SIR | Obs. | Exp. | SIR |
| Mouth | 2 | 2.7 | 0.7 | 1 | 1.1 | 0.9 |
| Gastrointestinal | 13 | 15.7 | 0.8 | 15 | 13.8 | 1.1 |
| Lung | 25 | 15.0 | 1.7** | 9 | 4.6 | 2.0** |
| Genital | 13 | 7.9 | 1.6 | 8 | 12.5 | 0.6 |
| Urinary | 7 | 6.0 | 1.2 | 1 | 2.4 | 0.4 |
| All Sites | 71 | 60.8 | 1.2 | 71 | 65.4 | 1.1 |
*Standardized Incidence Ratio (standardized
by age)
**p < 0.05
a) How would you interpret these data? Consider:
b) What further studies might you like to do to define potential cancer risk at Love Canal?
There does not appear to be a strong pattern of cancer excess in the Love Canal population however the sample size is probably too small for accurate estimates of risk to be made and the latency of exposure to the canal waste stream is probably too short to make conclusions. Using census track as an indication of exposure would probably result in many unexposed people being considered as exposed and bias the results towards the null. No data on individual risk factors is taken into account in such Ecologic Studies. Remember: No Evidence of an Effect IS NOT the same as Evidence of No Effect!
One could follow up with a case control study, look for geographic clusters and establish a cohort for subsequent follow up study.
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